What I done was take all the years with the DJF (DEC/JAN/FEB) periods that had between -0.5 and +0.5 then went onto the CET / mean temp lists took note of all the years Decembers, Januarys and Februarys mean temps then averaged it all out and then went back to the CET / mean temp lists and wrote any years DEC/JAN/FEB that had the same mean temp
https://www.metoffice.gov.uk/hadobs/hadcet/mly_cet_mean_sort.txt
https://www.metoffice.gov.uk/hadobs/hadcet/cetml1659on.dat
https://www.metoffice.gov.uk/pub/data/weather/uk/climate/datasets/Tmean/ranked/Scotland.txt
https://www.metoffice.gov.uk/pub/data/weather/uk/climate/datasets/Tmean/date/Scotland.txt
Just done the same calculations for East Scotland and got, DECEMBER 2.2 C, JANUARY 1.7 C , FEBRUARY 2.0 C
previous years with same mean temps
DECEMBER 2.2 - 1938
JANUARY - 1997
FEBRUARY - 1973, 1972, 1933, 1922

Have done some calculations based on the ENSO forecast for December / January / February I done the CET in another thread but here are the Scotland mean temperatures. DECEMBER 2.7 C , JANUARY 2.3 C , FEBRUARY 2.4 C and a list of DEC/JAN/FEB with those figures
DECEMBERS WITH 2.7 C - 1962
JANUARY'S WITH 2.3 C - 1954
FEBRUARIES WITH 2.4 C - 1965, 1944 & 1910
Not a forecast just to monitor and see how close / far away those end up being and purely based on ENSO and previous Scotland mean temp years.
when I get more time I will try and do some for each section of Scotland East / West etc.

Here in Kirkcaldy we get the Forth streamer with snow showers starting in the North Sea then moving into the firth of forth before arriving here, the 2 best I have experienced in my lifetime so far (I am 23) were November 2010 and February / March 2018 Beast From The East.
The perfect setup is as straight of an easterly flow as possible and 850 temps usually from -8 and below.
November 2010
Winds were alternating between east and north easterlies on the 27th with the first signs of the heavy snow arriving on the Saturday night
By midday on the 28th the flow was perfect with a straight easterly continuing to feed in non stop bands of heavy snow which were quickly piling up the snowfall amounts the easterly flow persisted even heading into the 30th some more forecasts of the event
I was living in a higher part of Kirkcaldy at the time and by the end of the event there was over a foot of snow. Some other youtube videos from Kirkcaldy of this event
February / March 2018
27th February 2018 saw the easterly begin to arrive up here with a bitter cold pool accompanying it through the night into the 28th the easterly strengthened with the gale force easterly winds blizzard conditions set in with the non stop snow showers and also plenty of thundersnow even here at 20m ASL by the end of the event again I had a foot of snow which is quite an achievement at that altitude, also was in the center of a RED snow warning from the met office
my pictures from the event
Another event that I remember vividly and one which delivered another few inches on top of what we had already got at that point in December 2010 and as stated the transport minister lost his job due to the chaos on the M8 https://www.telegraph.co.uk/news/uknews/scotland/8189583/Scotlands-Transport-Minister-urged-to-resign-over-snow-chaos.html
https://www.theguardian.com/uk/2010/dec/11/scottish-transport-minister-stewart-stevenson-resigns-snow
https://www.theguardian.com/uk/2010/dec/08/transport-secretary-scotland-perfect-storm
https://www.bbc.co.uk/news/uk-11924616
https://www.telegraph.co.uk/news/weather/8188603/Scotland-calls-in-the-Army-to-clear-snow-and-ice.html

Have done some calculations based on the ENSO forecast which for winter is between -0.5 and +0.5 years with December, January and February which fell within that bracket dating back to 1950 were 1951/52, 1952/53, 1956/57, 1959/60, 1960/61, 1961/62, 1962/63, 1966/67, 1969/70, 1974/75, 1978/79, 1980/81, 1981/82, 1985/86, 1989/90, 1990/91, 1992/93, 1993/94, 1996/97, 2001/02, 2003/04, 2012/13, 2013/14 and 2016/17, I then looked at all the CET for those December's January's and February's and averaging it all out came up with these three CET's for the upcoming DEC/JAN/FEB period, DECEMBER 4.4 C , JANUARY 3.9 C , FEBRUARY 4.1 C I then went back to the CET list and here are years with those figures in DEC/JAN/FEB
Decembers with 4.4 C CET - 2005, 1982, 1938, 1884, 1856, 1803, 1776, 1761, 1753, 1705 & 1702
January's with 3.9 C CET - 1972, 1961, 1951, 1868, 1862, 1849, 1788, 1728 & 1700
Februaries with 4.1 CET - 2009, 1960, 1839 & 1805
This is not a forecast just something to monitor and see how close / far away those CET figures end up being and is only based on ENSO / CET

Brilliant post as always Roger, one of my gut feelings for this winter is the risk of at least 2 big Atlantic storms with wind gusts 85 - 100 mph possibly focused more on Ireland and Northern England / Scotland, hopefully it doesn't end up being another 2013/14 like I said earlier, I would rather have relentless snow than wind and flooding. Also one of my dream scenarios would be a Christmas blizzard so that possible Christmas storm you mention ends up being one

speaking of him I see he is charging £10 for a PDF winter forecast and wait for it "Also includes important details of 'to be prepared for SNOW dates'..." How on earth anyone can even claim to know exact dates of snowfall is ridiculous. https://exactaweather.com/

TBH I would rather that kind of outlook than a zonal onslaught like 2013/14 IF it ended up like current predictions the hope would be for the higher pressure the the S/SW to move out west / north west and allow the lower pressure and colder air down from the north like December 2010 when the cold returned with a vengeance lets just wait and see where we end up plenty snow for everyone

Let the panicking commence personally I would rather just wait and see what the shorter range charts are showing as we head through November and toward winter, we all remember how quickly 2010 and the BFTE developed. And if anyone is interested in the forecast for USA / Canada https://www.almanac.com/old-farmers-almanac-2020-winter-forecast